This invention relates generally to mailing systems, and more particularly to a moistener system for moistening an envelope flap of an envelope being processed by a mailing machine.
Mailing systems, such as, for example, a mailing machine, often include different modules that automate the processes of producing mail pieces. The typical mailing machine includes a variety of different modules or sub-systems each of which performs a different task on the mail piece. The mail piece is conveyed downstream utilizing a transport mechanism, such as rollers or a belt, to each of the modules. Such modules could include, for example, a singulating module, i.e., separating a stack of mail pieces such that the mail pieces are conveyed one at a time along the transport path, a moistening/sealing module, i.e., wetting and closing the glued flap of an envelope, a weighing module, and a metering module, i.e., applying evidence of postage to the mail piece. The exact configuration of the mailing machine is, of course, particular to the needs of the user.
In the moistening/sealing module, a moistening device includes an apparatus for moistening the glue line on flaps of envelopes in preparation for sealing the envelopes in either a mailing machine or an inserter, and may also include a mechanism for moistening a tape. Moistening devices generally fall into two categories: contact and non-contact moistening systems. Contact moistening systems generally deposit a moistening fluid, such as, for example, water or water with a biocide, onto the glue line on a flap of an envelope by contacting the glue line with a wetted applicator. Non-contact systems generally spray the moistening fluid onto the envelope flap.
In contact systems, the wetted applicator typically consists of a contact media such as a brush, foam or felt. The applicator is, at least part of the time, in contact with a wick. The wick is generally a woven material, such as, for example, felt, or can also be a foam material. At least a portion of the wick is located in a reservoir containing the moistening fluid. The moistening fluid is transferred from the wick to the applicator by physical contact pressure between the wick and applicator, thereby wetting the applicator. An envelope flap is guided between the wick and the applicator, such that the applicator contacts the glue line on the flap of the envelope, thereby transferring the moistening fluid to the flap to activate the glue. The flap is then closed and sealed, such as, for example, by passing the closed envelope through a nip of a sealer roller to compress the envelope and flap together, and the envelope is then passed to the next module for continued processing.
There are problems, however, with conventional contact moistening systems. For example, in conventional contact moistening systems, it is difficult to accurately control the quantity of moistening fluid being transferred from the applicator to the envelope flap. If not enough moistening fluid is applied (“under-wetting”), the envelope flap will not properly seal to the envelope body. If too much moistening fluid is applied (“over-wetting”), the excess moistening fluid can cause damage to the envelope and/or its contents. Excessive moistening can also negatively impact any printing performed on the envelope, such as, for example, a postage indicium. For example, if the printing is being done by an ink-jet printer, an excessive amount of moisture will cause the ink to run, thereby possibly rendering any printed information illegible.
There are a number of factors which may cause variations in the degree of wetting of the moistening system applicator, and thus cause variations in the amount of moistening fluid applied to the envelope flap. Among these factors are: the number and/or rate of transport and/or size of envelopes processed by the moistening system; the level of moistening fluid in the reservoir; and environmental factors such as temperature, humidity, and/or altitude. Furthermore, in some cases where a high volume of mail is being processed in a limited time, the amount of moistening fluid that the wick can transfer to the applicator in a given period of time is insufficient to keep the applicator adequately moistened in view of the amount of moistening fluid being removed from the applicator by contact with envelope flaps.
Thus, there exists a need for a contact moistening system in which a greater quantity of moistening fluid can be transferred to the applicator within a given period of time and/or the amount of moistening fluid transferred to the applicator can be controlled to adapt to varying mail processing requirements and/or environmental conditions.